Electric pocket-lamp.



W. KRAFFT. ELECTRIC POCKET LAMP. APPLICATION FILED M16124, 1914.

1,099,381 Patented June 9, 1914.

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STATES PATENT OFFICE.

WALTER KRAFFT, 0F BERLIN, GERMANY.

ELECTRIC POCKET-LAMP.

Specification of Letters Patent.

Patented June 9, 1914.

Application filed'lanuary 24, 1914. Serial No. 814,224.

To all whom it may concern:

Be it known. that I, WALTER KnAFr'r, a subject of the Emperor of Germany, residing at Berlin, Germany, have invented certain Improvements in or Relating to Electric Pocket-Lamps, of which the following is a specification.

The filaments of electric pocket lamps frequently fuse, particularly after a renewal of the battery. This is due to the fact that the tension of a fresh battery amounts to about 4.2 to L4 volt, while the bulbs are usually only made for a tension of 3.5 volt. The trouble is aggravated by the use of good batteries which only slowly drop their voltage.

The object of the present invention is to eliminate this disadvantage and it is achieved by the provision of a series resistance which is placed on one of the contact springs so as to form part of the circuit, the arrangement being such that the resistance can easily be put out of action when the voltage of the battery has dropped to a safe magnitude. By this arrangement, therefore, the efliciency of the lamp will be enhanced and a saving of bulbs will be eilected.

The resistance is composed of a coil which is inclosed together with an insulation between two flattened nested sleeves adapted to clamp themselves in various positions to one of the contact springs of the battery.

In the accompanylng drawings the inven- Figure 1 representmg ai-v tion is illustrated, side view of a battery having the resistance applied to one of the contact springs. Fig. 2 is an end view of the resistance, Fig. 3, a longitudinal section, and Fig. 4, a perspective view of the same.

A flattened sleeve (1 of suitable material such as German silver, copper, brass or the like, has Within it another sleeve 7) from which it is spaced so that a resistance coil d can be housed bctwecnthe two. Layers f and g of insulation separate the sleeves from the coil which is moreover embedded in insulating material 6 fillin up all superfluous space and holding the elements together. If the coil.is careiiilly embedded 1n the material 6, the layers f and' g may be omitted. One end of the coil (1 is connected'to the sleeve a and the other to the sleeve 1; so that an electric current can pass through the coil from one sleeve to the other. The structure thus formed is applied to one of the contact springs i of the battery it, as shown in Fig. 1, preferably so. as to contact with the bulb. The current must therefore pass through the coil which reduces the voltage. After the voltage of the battery has dropped, which will be evident by a weakening of the light, the device is slid on the spring 2' into the position shown dotted in Fig. 1 so that the spring can contact directly wlth the bulb for transmitting the full voltage of the battery to the lamp. The sleeve 2) is contracted at 0 so as to produce a clamping efiect for holding the device in any desired position 'on thespring i.

-The actual construction of the resistance may be varied within the scope of the invention which consists, as previously noticed, in the provision of a series resistance which is capable of retaining itself on one of the contact springs of an electric pocket lamp so as to form part of the circuit.

1. The combination with an electric pocket lamp having a battery with contact springs,

of a series resistance, and means for holding said resistance on one of the contact springs so as to form part of the circuit, substan- -tially as and for the purpose set forth.

2. The combination with an electric pocket lamp having a battery with contact springs, of two flattened nested sleeves spaced by means of an insulation, a resistance coil embedded in said insulation and having its ends connected to the sleeves one to each, the sleeves being made so that they can be applied to one of said contact springs for transmitting the current by means of the coil, substantially as and for the purpose set forth.

3. The combination with an electric pocket lamp having a battery with contact springs, of two flattened nested sleeves spaced by m ans ofan insulation, a resistance coil embedded within said insulation and having its ends connected to the sleeves one to each,

the structure thus obtained being adapted to operative position, substantially as and for b; slllid by means of the inner slfeeve 031:0 one the purpose set forth. "-0 t e contact springs so as to orm t e 0011- i tact and transmit the current by means of R KRAFFT' the coil, the inner sleeve being contracted so Witnesses: as to clamp the contact spring and hold the 'WOLDEMA HAUPT, structure on the latter out of as Well as in HENRY HASPER. 

